This cascade circuit was obtained from old Signetics documentation. The circuit makes use of special neon lamps that act as valves. Observe the high supply voltage.
The circuit presented is based on a mechanical tuning fork. The circuit is suggested by National...
This source, from a 1982 documentation, uses a triac to control the power and voltage applied to...
This circuit was found in a 1990 Electronics World magazine. The circuit can be mounted today by...